A big part is that the processed foods of America make us have drug like cravings for things we consume too much of, salt, fat, sugar, etc. Get em hooked, it’s good for profit.

It's also systemic. We only need about 300-400mg of sodium per day. The reason the DV amount is 1500-2400mg is because the people that decided it knew Americans wouldn't be willing to accept a number that low. So it's a feedback cycle between the processed foods industry and public demand